1. Field of the Invention
The present invention relates to a camera and an exposure control method. More particularly, the present invention relates to a camera and an exposure control method in which information of photosensitivity of photo film to be used for exposure control can be input both manually and automatically.
2. Description Related to the Prior Art
A camera of the Brownie type is used with 120 or 220 type of roll photo film. There are very few cameras of this type that have automatic structures of focussing and photo film loading. It is extremely complex to handle the Brownie type in contrast to compact cameras, single-lens reflex cameras and the like for use with the 135 type or the IX 240 type. There is no well-known technique of facilitating photography with high image quality with a camera of the Brownie type, except for very recently marketed models of this type incorporating an autofocussing device.
A roll photo film does not have an information signaling portion like a DX code of an 135 photo film cassette disposed outside its cassette shell. The roll photo film has no such structure for sending a camera photo film information including photosensitivity of the roll photo film, the number of available frames of the photo filmstrip of the roll photo film and the like. It is general that the camera for use with the roll photo film has a photosensitivity dial, in which a train of numerals is disposed on the dial for indicating values of the photosensitivity. A pointer is disposed on the camera body and near to the dial, and adapted to pointing one of the numerals of the dial being rotated, for selectively inputting manual input photosensitivity information to the camera.
There is a commonly assigned co-pending patent application U.S. Ser. No. 08/712,387, now U.S. Pat. No. 5,845,869 (corresponding to EP-A 0 763 768), in which an adhesive connective tape in connection with the light-shielding sheet and the photo filmstrip has a prerecorded bar code. The camera automatically reads the bar code, and sets the photosensitivity for exposure control.
In most cases of taking a photograph, the photosensitivity is input in the camera at an equal value to the nominal value of the photosensitivity of the roll photo film to be exposed. Consequently the automatic photosensitivity setting system is more convenient than, and advantageous over, the manual photosensitivity setting system. However skilled amateur photographers or professional photographers frequently wish to input the photosensitivity changed from the nominal value by a certain amount, for example from 1/3 EV to 2 EV. Assuming that the roll photo film is negative color photo film with the photosensitivity of ISO 100, the contrast would be heightened if the photosensitivity is raised by +1/3 EV to set ISO 80 in a temporary manner. A photograph taken against back light would be acceptably taken if the photosensitivity is raised by +2 EV to set ISO 25 in a temporary manner. However there has been no known structure in which photosensitivity information of photo film to be used for the exposure control would be set both manually and automatically. Such users as skilled amateur photographers and professional photographers have not been satisfied with known cameras of the Brownie type.